This invention relates to dual service fittings for underfloor wireway systems, and more particularly to an improved dual service fitting of the type known as a dual pre-set insert. Such a service fitting is designed to be mounted on a cellular steel floor before pouring of the concrete and bridges a pair of adjacent cells of the steel floor which respectively contain power and communication wiring. It provides for protected access to those cells.
A cellular steel floor comprises a plurality of floor sections presenting alternate parellel crests and troughs defining a plurality of elongated channels or cells providing passages for air flow, electrical power and communication wiring, piping and various other purposes. Concrete is poured over the cellular floor sections to form a completed floor except for a floor covering such as tile or carpet.
In order for a cellular steel floor to function as a viable component of the communication and electric power systems of a building, access to the cells may be provided at selected intervals. Access to the cells may be provided by either "afterset" inserts or "preset" inserts. An afterset insert is installed after the concrete has hardened by cutting a core from the concrete fill above the cellular steel floor, removing the concrete core, and then cutting a hole in the upper wall of a cell for reception of the afterset insert. In the case of a pre-set insert, an opening is formed in the upper wall of a cell prior to pouring the concrete and an insert or service fitting having a height substantially equal to the depth of the concrete pour is mounted on the cell prior to the concrete pour. After the pour, a thin layer of concrete normally overlies the insert. This layer of concrete is chipped away to provide access to the insert, and a suitable cover plate is installed on the insert.
Typically, adjacent cells of a cellular steel floor respectively contain power and communication wiring, and it is desirable that a so-called dual service fitting or insert be provided so that access to either the electric power or communication wiring or both can be provided through a single fitting.